Showing papers on "Wireless Routing Protocol published in 2000"

Energy-efficient communication protocols for wireless microsensor networks

Abstract: Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have signicant impact on the overall energy dissipation of these networks. Based on our ndings that the conventional protocols of direct transmission, minimum-transmission-energy, multihop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster base stations (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show that LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional routing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.

GPSR: greedy perimeter stateless routing for wireless networks

Abstract: We present Greedy Perimeter Stateless Routing (GPSR), a novel routing protocol for wireless datagram networks that uses the positions of routers and a packet's destination to make packet forwarding decisions. GPSR makes greedy forwarding decisions using only information about a router's immediate neighbors in the network topology. When a packet reaches a region where greedy forwarding is impossible, the algorithm recovers by routing around the perimeter of the region. By keeping state only about the local topology, GPSR scales better in per-router state than shortest-path and ad-hoc routing protocols as the number of network destinations increases. Under mobility's frequent topology changes, GPSR can use local topology information to find correct new routes quickly. We describe the GPSR protocol, and use extensive simulation of mobile wireless networks to compare its performance with that of Dynamic Source Routing. Our simulations demonstrate GPSR's scalability on densely deployed wireless networks.

Epidemic routing for partially-connected ad hoc networks

Abstract: Mobile ad hoc routing protocols allow nodes with wireless adaptors to communicate with one another without any pre-existing network infrastructure. Existing ad hoc routing protocols, while robust to rapidly changing network topology, assume the presence of a connected path from source to destination. Given power limitations, the advent of short-range wireless networks, and the wide physical conditions over which ad hoc networks must be deployed, in some scenarios it is likely that this assumption is invalid. In this work, we develop techniques to deliver messages in the case where there is never a connected path from source to destination or when a network partition exists at the time a message is originated. To this end, we introduce Epidemic Routing, where random pair-wise exchanges of messages among mobile hosts ensure eventual message delivery. The goals of Epidemic Routing are to: i) maximize message delivery rate, ii) minimize message latency, and iii) minimize the total resources consumed in message delivery. Through an implementation in the Monarch simulator, we show that Epidemic Routing achieves eventual delivery of 100% of messages with reasonable aggregate resource consumption in a number of interesting scenarios.

Mitigating routing misbehavior in mobile ad hoc networks

Abstract: This paper describes two techniques that improve throughput in an ad hoc network in the presence of nodes that agree to forward packets but fail to do so. To mitigate this problem, we propose categorizing nodes based upon their dynamically measured behavior. We use a watchdog that identifies misbehaving nodes and a pathrater that helps routing protocols avoid these nodes. Through simulation we evaluate watchdog and pathrater using packet throughput, percentage of overhead (routing) transmissions, and the accuracy of misbehaving node detection. When used together in a network with moderate mobility, the two techniques increase throughput by 17% in the presence of 40% misbehaving nodes, while increasing the percentage of overhead transmissions from the standard routing protocol's 9% to 17%. During extreme mobility, watchdog and pathrater can increase network throughput by 27%, while increasing the overhead transmissions from the standard routing protocol's 12% to 24%.

Performance comparison of two on-demand routing protocols for ad hoc networks

Abstract: Ad hoc networks are characterized by multi-hop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols. We compare the performance of two prominent on-demand routing protocols for mobile ad hoc networks - dynamic source routing (DSR) and ad hoc on-demand distance vector routing (AODV). A detailed simulation model with MAC and physical layer models is used to study inter-layer interactions and their performance implications. We demonstrate that even though DSR and AODV share a similar on-demand behavior the differences in the protocol mechanics can lead to significant performance differentials. The performance differentials are analyzed using varying network load, mobility and network size. Based on the observations, we make recommendations about how the performance of either protocol can be improved.

Location-aided routing (LAR) in mobile ad hoc networks

Abstract: A mobile ad hoc network consists of wireless hosts that may move often. Movement of hosts results in a change in routes, requiring some mechanism for determining new routes. Several routing protocols have already been proposed for ad hoc networks. This paper suggests an approach to utilize location information (for instance, obtained using the global positioning system) to improve performance of routing protocols for ad hoc networks. By using location information, the proposed Location‐Aided Routing (LAR) protocols limit the search for a new route to a smaller “request zone” of the ad hoc network. This results in a significant reduction in the number of routing messages. We present two algorithms to determine the request zone, and also suggest potential optimizations to our algorithms.

AODV-BR: backup routing in ad hoc networks

Abstract: Nodes in mobile ad hoc networks communicate with one another via packet radios on wireless multihop links. Because of node mobility and power limitations, the network topology changes frequently. Routing protocols therefore play an important role in mobile multihop network communications. A trend in ad hoc network routing is the reactive on-demand philosophy where routes are established only when required. Most of the protocols in this category, however, use a single route and do not utilize multiple alternate paths. We propose a scheme to improve existing on-demand routing protocols by creating a mesh and providing multiple alternate routes. Our algorithm establishes the mesh and multipaths without transmitting any extra control message. We apply our scheme to the Ad-hoc On-Demand Distance Vector (AODV) protocol and evaluate the performance improvements by simulation.

Fisheye state routing: a routing scheme for ad hoc wireless networks

Abstract: This paper presents a novel routing protocol for wireless ad hoc networks-fisheye state routing (FSR). FSR introduces the notion of multi-level fisheye scope to reduce routing update overhead in large networks. Nodes exchange link state entries with their neighbors with a frequency which depends on distance to destination. From link state entries, nodes construct the topology map of the entire network and compute optimal routes. Simulation experiments show that FSR is a simple, efficient and scalable routing solution in a mobile, ad hoc environment.

IEEE 802.11 protocol: design and performance evaluation of an adaptive backoff mechanism

Abstract: In WLANs, the medium access control (MAC) protocol is the main element that determines the efficiency of sharing the limited communication bandwidth of the wireless channel. The fraction of channel bandwidth used by successfully transmitted messages gives a good indication of the protocol efficiency, and its maximum value is referred to as protocol capacity. In a previous paper we have derived the theoretical limit of the IEEE 802.11 MAC protocol capacity. In addition, we showed that if a station has an exact knowledge of the network status, it is possible to tune its backoff algorithm to achieve a protocol capacity very close to its theoretical bound. Unfortunately, in a real case, a station does not have an exact knowledge of the network and load configurations (i.e., number of active stations and length of the message transmitted on the channel) but it can only estimate it. In this work we analytically study the performance of the IEEE 802.11 protocol with a dynamically tuned backoff based on the estimation of the network status. Results obtained indicate that under stationary traffic and network configurations (i.e., constant average message length and fixed number of active stations), the capacity of the enhanced protocol approaches the theoretical limits in all the configurations analyzed. In addition, by exploiting the analytical model, we investigate the protocol performance in transient conditions (i.e., when the number of active stations sharply changes).

A performance comparison study of ad hoc wireless multicast protocols

Abstract: In this paper we investigate the performance of multicast routing protocols in wireless mobile ad hoc networks. An ad hoc network is composed of mobile nodes without the presence of a wired support infrastructure. In this environment, routing/multicasting protocols are faced with the challenge of producing multihop routes under host mobility and bandwidth constraints. In recent years, a number of new multicast protocols of different styles have been proposed for ad hoc networks. However, systematic performance evaluations and comparative analysis of these protocols in a common realistic environment has not yet been performed. In this study, we simulate a set of representative wireless ad hoc multicast protocols and evaluate them in various network scenarios. The relative strengths, weaknesses, and applicability of each multicast protocol to diverse situations are studied and discussed.

Multicast tree construction and flooding in wireless ad hoc networks

Abstract: In an ad hoc network, each host assumes the role of a router and relays packets toward final destinations. This paper studies efficient routing mechanisms for multicast and broadcast in ad hoc wireless networks. Because a packet is broadcast to all neighboring nodes, the optimality criteria of wireless network routing is different from that of wired network routing. In this paper, we point out that the number of packet forwarding is the more important cost factor than the number of links in the ad hoc network. After we show constructing minimum cost multicast tree is hard, we propose two new flooding methods, self pruning and dominant pruning. Both methods utilize neighbor information to reduce redundant transmissions. Performance analysis shows that both methods perform significantly better than blind flooding. Especially, dominant pruning performs close to the practically achievable best performance limit.

LANMAR: landmark routing for large scale wireless ad hoc networks with group mobility

Abstract: In this paper, we present a novel routing protocol for wireless ad hoc networks-landmark ad hoc routing (LANMAR). LANMAR combines the features of fisheye state routing (FSR) and landmark routing. The key novelty is the use of landmarks for each set of nodes which move as a group (e.g., a team of co-workers at a convention or a tank battalion in the battlefield) in order to reduce routing update overhead. Like in FSR, nodes exchange link state only with their neighbors. Routes within the fisheye scope are accurate, while routes to remote groups of nodes are "summarized" by the corresponding landmarks. A packet directed to a remote destination initially aims at the landmark; as a gets closer to the destination it eventually switches to the accurate route provided by fisheye. Simulation experiments show that LANMAR provides efficient and scalable routing in large, mobile, ad hoc environments in which group mobility applies.

Power-aware localized routing in wireless networks

Abstract: Two metrics where transmission power depends on distance between nodes, and a cost aware metric based on remaining battery power at nodes (assuming constant transmission power), together with corresponding non-localized shortest path routing algorithms, were recently proposed. We define a new power-cost metric based on the combination of both node's lifetime and distance based power metrics. We then propose power, cost, and power-cost GPS based localized routing algorithms, where nodes make routing decisions solely on the basis of location of their neighbors and destination. Power aware localized routing algorithm attempts to minimize the total power needed to route a message between a source and a destination. Cost-aware localized algorithm is aimed at extending battery's worst case lifetime. The combined power-cost algorithm attempts to minimize the total power needed and to avoid nodes with short remaining lifetime. We prove that these localized power, cost, and power-cost efficient routing algorithms are loop-free.

Caching strategies in on-demand routing protocols for wireless ad hoc networks

Abstract: An on-demand routing protocol for wireless and hoc networks is one that searches for and attempts to discover a route to some destination node only when a sending node originates a data packet addressed to that node. In order to avoid the need for such a route discovery to be performed before each data packet is sent, such routing protocols must cache routes previously discovered. This paper presents an analysis of the effects of different design choices for this caching in on-demand routing protocols in wireless ad hoc networks, dividing the problem into choices of cache structure, cache capacity, and cache timeout. Our analysis is based on the Dynamic Source Routing protocol (DSR), which operates entirely on-demand. Using detailed simulations of wireless ad hoc networks of 50 mobile nodes, we studied a large number of different caching algorithms that utilize a range of design choices, and simulated each cache primarily over a set of 50 different movement scenarios drawn from 5 different types of mobility models. We also define a set of new mobility metrics that allow accurate characterization of the relative difficulty that a given movement scenario presents to an ad hoc network routing protocol, and we analyze each mobility metric's ability to predict the actual difficulty in terms of routing overhead experienced by the routing protocol across the scenarios in our study.

Fisheye State Routing in Mobile Ad Hoc Networks.

Abstract: In this paper, we present a novel routing protocol for wireless ad hoc networks – Fisheye State Routing (FSR). FSR introduces the notion of multi-level fisheye scope to reduce routing update overhead in large networks. Nodes exchange link state entries with their neighbors with a frequency which depends on distance to destination. From link state entries, nodes construct the topology map of the entire network and compute optimal routes. Simulation experiments show that FSR is simple, efficient and scalable routing solution in a mobile, ad hoc environment.

MIPMANET: mobile IP for mobile ad hoc networks

Abstract: Mobile ad hoc networking allows nodes to form temporary networks and communicate beyond the transmitter range by supporting multihop communication through IP routing. Routing in such networks is often reactive, i.e., performed on-demand, as opposed to Internet routing that is proactive. As ad hoc networks are formed on a temporary basis, any IP address should be allowed to appear in an ad hoc network. This paper presents MIPMANET, a solution for connecting an ad hoc network, in which on-demand routing is used, to the Internet. MIPMANET provides Internet access by using mobile IP with foreign agent care-of addresses and reverse tunneling. This allows nodes to enjoy the mobility services of mobile IP while at the same time the requirements on the ad hoc routing protocol are kept to a minimum. Simulations of MIPMANET have been performed in the Network Simulator 2. The ad hoc on-demand distance vector (AODV) routing protocol has been used for routing within the ad hoc network. These simulations show that the ability to choose the closest access point to the Internet is worth extra work, as less traffic is generated in the network resulting in lower delays and fewer dropped packets.

Dynamic routing of bandwidth guaranteed tunnels with restoration

Abstract: This paper presents new algorithms for dynamic routing of restorable bandwidth-guaranteed paths. A straightforward solution for the restoration problem is to find two disjoint paths. However, this results in excessive resource usage for backup paths and does not satisfy the implicit service provider requirement of optimizing network resource utilization so as to increase the number of potential future demands that can be routed. We give an integer programming formulation for this problem which is new. Complete path routing knowledge is a reasonable assumption for a centralized routing algorithm. However, it requires maintenance of non-aggregated or per-path information which is not often desirable particularly when distributed routing is preferred. We show that a partial information scenario which uses only aggregated and not per-path information provides sufficient information for a suitably developed algorithm to be able to perform almost as well as the complete information scenario. In this partial information scenario the routing algorithm only knows what fraction of each link's bandwidth, is currently used by active paths, and is currently used by backup paths. Obtaining this information is feasible using proposed traffic engineering extensions to routing protocols. We formulate the dynamic restorable bandwidth routing problem in this partial information scenario and develop efficient routing algorithms. We compare there routing performance of this algorithm to a bound obtained using complete information. Our partial information-based algorithm performs very well and its performance in terms of the number of rejected requests is very close to the full information bound.

Mobility prediction in wireless networks

Abstract: Wireless networks allow a more flexible communication model than traditional networks since the user is not limited to a fixed physical location. Unlike cellular wireless networks, ad hoc wireless networks do not have any fixed communication infrastructure. In ad hoc networks, routes are mostly multihop and network hosts communicate via packet radios. Each host moves in an arbitrary manner and thus routes are subject to frequent disconnections. In typical mobile networks, nodes exhibit some degree of regularity in the mobility pattern. By exploiting a mobile user's non-random traveling pattern, we can predict the future state of network topology and thus provide a transparent network access during the period of topology changes. In this paper we present various enhancements to unicast and multicast routing protocols using mobility prediction. The proposed scheme utilizes GPS location information. By simulation, we evaluate the effectiveness of mobility prediction.

Multipath source routing in wireless ad hoc networks

Abstract: We propose a new multipath routing protocol for ad hoc wireless networks-multipath source routing (MSR), which is based on DSR (dynamic source routing). MSR extends DSR's route discovery and route maintenance mechanism to deal with multipath routing. Based on the measurement of RTT, we propose a scheme to distribute load between multiple paths. The simulation results show that our approach improves the throughput of TCP and UDP and the packet delivery ratio, and reduces the end-to-end delay and the queue size, while adding little overhead. As a result, MSR decreases the network congestion quite well.

Simulation-based performance evaluation of routing protocols for mobile ad hoc networks

Abstract: In this paper we evaluate several routing protocols for mobile, wireless, ad hoc networks via packetdlevel simulations. The ad hoc networks are multidhop wireless networks with dynamically changing network connectivity owing to mobility. The protocol suite includes several routing protocols specifically designed for ad hoc routing, as well as more traditional protocols, such as link state and distance vector, used for dynamic networks. Performance is evaluated with respect to fraction of packets delivered, enddtodend delay, and routing load for a given traffic and mobility model. Both small l30 nodesr and medium sized l60 nodesr networks are used. It is observed that the new generation of onddemand routing protocols use much lower routing load, especially with small number of peerdtodpeer conversations. However, the traditional link state and distance vector protocols provide, in general, better packet delivery and enddtodend delay performance.

An implementation study of the AODV routing protocol

Abstract: The Ad hoc On-Demand Distance Vector (AODV) routing protocol is designed for use in ad hoc mobile networks. Because of the difficulty of testing an ad hoc routing protocol in a real-world environment, a simulation was first created so that the protocol design could be tested in a variety of scenarios. Once simulation of the protocol was nearly complete, the simulation was used as the basis for an implementation in the Linux operating system. In the course of converting the simulation into an implementation, certain modifications were needed in AODV and the Linux kernel due to both simplifications made in the simulation of AODV and to incompatibilities of the Linux kernel and the IP-layer to routing in a mobile environment. This paper details many of the changes that were necessary during the development of the implementation.

GeoTORA: a protocol for geocasting in mobile ad hoc networks

Abstract: This paper considers the problem of providing a geocast service in mobile ad hoc networks and presents a novel geocasting algorithm combining unicasting and flooding. Geocast is useful for sending messages to everyone in a specified geographical region. The proposed protocol is named GeoTORA, because it is derived from the TORA (unicast) routing protocol. Flooding is also incorporated in GeoTORA, but it is limited to nodes within a small region. This integration of TORA and flooding can significantly reduce the overhead of geocast delivery while maintaining reasonably high accuracy.

Geographic routing for wireless networks

Abstract: Distributed shortest-path routing protocols for wired networks either describe the entire topology of a network or provide a digest of the topology to every router. They continually update the state describing the topology at all routers as the topology changes to find correct routes for all destinations. Hence, to find routes robustly, they generate routing protocol message traffic proportional to the product of the number of routers in the network and the rate of topological change in the network. Current ad-hoc routing protocols, designed specifically for mobile, wireless networks, exhibit similar scaling properties. It is the reliance of these routing protocols on state concerning all links in the network, or all links on a path between a source and destination, that is responsible for their poor scaling. We present Greedy Perimeter Stateless Routing (GPSR), a novel routing protocol for wireless datagram networks that uses the positions of routers and a packet's destination to make packet forwarding decisions. GPSR makes greedy forwarding decisions using only information about a router's immediate neighbors in the network topology. When a packet reaches a region where greedy forwarding is impossible, the algorithm recovers by routing around the perimeter of the region. By keeping state only about the local topology, GPSR scales better in per-router state than shortest-path and ad-hoc routing protocols as the number of network destinations increases. Under mobility's frequent topology changes, GPSR can use local topology information to find correct new routes quickly. We describe the GPSR protocol, and use extensive simulation of mobile wireless networks to compare its performance with that of Dynamic Source Routing. Our simulations demonstrate GPSR's scalability on densely deployed wireless networks.

On-demand routing in large ad hoc wireless networks with passive clustering

Abstract: This paper presents on-demand routing scalability improvements achieved using a "passive" clustering. Any on-demand routing typically requires some form of flooding. Clustering can dramatically reduce transmission overhead during flooding. In fact, by using clustering, we restrict the set of forwarding nodes during flood search and thus reduce the energy cost and traffic overhead of routing in dynamic traffic and topology environments. However existing "active" clustering mechanisms require periodic refresh of neighborhood information and tend to introduce quite a large amount of communication maintenance overhead. We introduce a passive clustering protocol scheme which is mostly supported/maintained by user data packets instead of explicit control packets. The passive scheme is consistent with the on-demand routing philosophy. Simulation results show significant performance improvements when passive clustering is used.

GeoGRID: A Geocasting Protocol for Mobile Ad Hoc Networks Based on GRID

Abstract: A mobile ad hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. One prospective direction to use such networks is to adopt positioning devices (such as global positioning system, GPS) to provide location-aware services. This paper discusses an attractive service called geocasting, or location-based broadcasting, whose goal is to send a message targeted at mobile host resident within a specified geographical region (such as a building, a street, a commercial area, etc.). In this paper, we propose a new routing protocol for geocasting called GeoGRID, which is based on our earlier unicast protocol GRID [14]. The protocol is featured by utilizing location information, confining the flooding zone, and electing a special host in each grid area responsible of forwarding the geocast messages. Simulation results show that our GeoGRID protocol can reduce network traffic and achieve higher data arrival rate.

Route-lifetime assessment based routing (RABR) protocol for mobile ad-hoc networks

Abstract: Owing to the absence of any static support structure, ad-hoc networks are prone to link failures. The 'shortest path seeking' routing protocols may not lead to stable routes. The consequent route failures that ensue, lead to the degradation of system throughput. This paper suggests a routing protocol wherein the route selection is done on the basis of an intelligent residual lifetime assessment of the candidate routes. Schemes for performance enhancement with TCP and non-TCP traffic in ad-hoc networks are proposed. The protocol is backed by simulations in ns that show excellent adaptation to increasing network mobility. We have also introduced new route cache management and power aware data transmission schemes.